In our tests, the app didn't do a very good job of emulating the genuine Instagram app, but that may be because it failed to find the correct network operator. Because this is a malicious app that seems to be relying in the sending of background SMS messages to earn its creators revenue.

In other words, the app can read your text messages and could potentially install malware on your phone. If the newly downloaded Instagram on your Galaxy S II is acting funny, it's probably good to ensure you've got the real app.